Internal combustion engine



De 9, 1958 P; MARIETTI 2,863,431

INTERNAL coMBusTIoN ENGINE Filed May 24, 1957 2 sheets-sheet 1 INVENTOR.

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Dec. 9, 1958 P. MARIETTI 2,863,431

INTERNAL COMBUSTION ENGINE Filed May 24, 1957 2 Sheets-Sheet 2 Unitedrates Patent Patented Dec. 9, 1958 tice This 'invention relates to newand useful improvements in internal combustion engines, and-it isdirected more particularly to improvementsifn` the valve actuatingmechanism thereof.

The principal object of the invention is directed to the `provisionfof ameans for association with thevalve actuating means 'of an internalcombustion engine. More particularly,rthe novel feature of the inventionis directed to the provision of a Wedge or cam member disposed between`the adjacent ends `of a rocker arm and valve stem which `is-constructed and arranged so as to eliminate the clearanceor spacingbetween the said adjacent ends of the rocker arm and valve stem therebyto insure a more direct loperation of the valve as well as theelimination of objectionable noise whilst effecting ,an improvedetciency in the operation of the engine.

In engines, where the end of a rocker arm in the valveopeningoscillation of the arm abuts the end of the valve stemso as toopen thevalve against its closing spring, there is a noisy impact which isobjectionable.

A clearance space, in the adjustment of the valve operating mechanism,is provided between the end of the rocker arm and the end of the valvestem so as to accom- `modate elongation ofthe valve stem as it becomesheated by the operation of the engine. in some cases, adjustments aremade while the engine is cold; in other cases, after the engine hasheated up. In all cases, there is at `least some clearance space, whenit is operating at its normal operating temperature, so that thereexists the objectionable noisy impact on the opening of each inlet andexhaust valve.

During the operation of an engine,`and under various conditions ofoperating temperature, the valves and associated partsthereof may expandor contract so as to re- `duce or increase the clearance space. Theabsolute correct spacing for all operating conditions is never de-`nnitely known, although a certain predetermined clearanice,l or` spacing` is recommended.

Where the clearance .space is insucient, when the ,engine is heated up,the valves do `not close properly. ,Likewise, when the clearance` is toogreat, the valves are V-Vention, Additionally, the rvalve is fullyseated in its closed position, and isful'ly opened to the degreeintended in is open position, thereby resulting in improved engineefficiency with respect to power and fuel consumption.

According to the present practise, attempts are made to adjust themechanism so as to provide a certain `specied clearance space betweenthe end of the rockerarm end and the end of the valve stetr suchprocedure is dithcult. In some cases it is made more diicult by thecondition of the ends of the Valve stem or rocker arm, or both.

According to this invention, adjustments are made in the valve`operating mechanism with the novel device in place between the ends ofthe rocker arm and valve stem,

-and said adjustments may be made with the engine in either cold orwarmed up condition.

Various changes may be made in the form of the device without departingfrom the `spirit and scope of the invention which for purposes ofdisclosure is shown and described in the form thereof presentlypreferred.

Inthe drawings;

' Fig. 1 is a vertical sectional View through the upper por tion of theblock and head of an internal combustion engine'having the novelfeatures of the invention associated. therewith;

Fig. 2 is an elevational View of adjacent end portions 4of the valveoperating arm and valve stem with the device of the invention associatedtherewith;

Fig. 3 isa view, similar to Fig. 2, showing the parts in a differentrelation so as to explain the operation of the device of the invention;and

Fig. 4 is a perspective View ofthe device of the invention.

Referring now to the drawings in detail, the invention will be fullydescribed. `It will Ibe understood that so much of an internalcombustion engine is shown as will aid in disclosing the invention.

`The upper portion of an engine block is represented by 2, `to which issecured, in the well known manner, a cylinder head 4, with the usualgasket 6 disposed between said block and head.

A cylinder is shown at 8 having a piston 10 reciprocable therein. Aconnecting-rod 12, connected by a wrist pin 13 to the piston, isoperable by a crank shaft (not shown) in the well known manner.

A rocker arm shaft 14 is supported by suitable su-pports, such as 16,and a plurality of rocker arms 18 are oscillatable thereon.

A valve 20 has a stem 22 reciprocable in the head 4 for movements of thevalve between a closed position on its seat, as shown, and an openposition away therefrom, all as is conventional. A compression spring 24around the valve stern ZZ is surmounted Aby a washer 2o which is held inplace by the usual key or pin 28.

A space 3) above the valve 2li may be connected to the fuel inlet or tothe exhaust outlet of theengine. The valve shown may, of course, be aninlet or an exhaust valve.

A threaded member 52 is provided in the outer end of the rocker arm anda lock nut 3d is in threaded engagement therewith.

A camshaft is represented by 36 and hasa lifting cam 38 fixed thereto. Alifter 4t) is reciprocable in the engine block, and a push or lift rod42 having a balland socket connection 44 with the member 32 has a lowerend `supported by the lifter.

Normally, as the cam 38 rotates in one direction, the rod is movedupwardly to swing the rocker arm 1.8, clockwise in valve-openingdirection against the action of the spring 24. Subsequently, the valveis reciprocated to closed position by the said spring 24, the stem 22lacting upwardlyon the rocker arm to swing it counterclockwise.

According to.y the invention, a spacer or space-closing. member isprovided which is interposed between the upper end of the valve stem 22and the stern actuating face 52 of the rocker arm 18 at the inner endthereof.

Said space-closing member 50 is of wedge shape longitudinally, and hasan' upper face 54 arranged angularly relative to a lower face.' Theincluded angle between the upper and lower faces of the member 50 may bevaried .as desired, but very satisfactory operation has been obtainedwith an angle in the neighborhood of eight (8) degrees.

If desired, one of the faces of the member 50 may be groovedlongitudinally, as at 56, for slidably seating said member on the upperend of the valve stem 22. The grooved portion may comprise a separatemember fixed to the wedge 50, if so desired.

Spring means is provided for urging the member 50 transversely relativeto the axis of the valve stern for the wedging action of said member 50between the top of the valve stem and the surface 52 of the rocker arm.

Said spring means may take any form desired but, for purposes ofdisclosure, a tension spring 58 is shown having one end 60 looped in anaperture 51 through the member 50 and an opposite end 64 looped aroundthe rod 42. l

The spring means will be such as to urge the member 50 sufciently inwhat may be called a wedging direction and therby to close the spacebetween the valve rod and rocker arm surface. The said spring means Willnot, of course, at any time exert such a sufficient force as to causethe member 50 to influence any downward movement of the valve stemagainst the valve spring 24.

The parts, as shown in Fig. 1, are in the rest position thereof with thevalve in its closed position, and with the member 50 closing the spacebetween the upper end of the valve stem and the arm surface 52. Thescrew 34 will be adjusted so as to close or ll up the space with themember 50 disposed substantially centrally of the valve stem, about asshown.

In this rest position, a point '70, indicated on the arm surface 52 isshown on the longitudinal axis a of the valve stem.

In operation of the engine and with the rocker arm oscillating in aclockwise valve-opening direction, the surface 52 of the said rocker armmoves along or slides on the upper inclined surface 54 of the member 50so as to act on the valve stem.

In this valve opening oscillation of the rocker arm, the point 70 swingson the arc of a circle having an axis on the axis of oscillation of saidarm whereby said point 70 moves to the left, towards a line B extendingthrough the axis of oscillation of said arm, a distance indicated by 71.Obviously in this oscillation of the arm, and as the surface 52 slideson the member 50, the point 70 is moved transversely away from the axisa of the stem through a distance indicated by 72, as shown in Fig. 2.

In the reverse counterclockwise valve-closingoscillation of the arm fromthe position shown in Fig. 2, the surface 52 of the arm acts on theupper surface 54 of the member 50 to slidably move said member on thestem to the right a distance substantially equal to the distance 72.

That is, a line such as 74 on the member is moved to the right relativeto the axis a of the stem a distance represented by 76, as shown in Fig.3. Spring 24 acts on the valve stem on the upward reverse oscillation ofthe arm to move said valve to its closed position.

In the instantaneous upper position of the surface 52 of the arm, andwith the valve closed on its seat, the spring 58 urges the member 50 tothe left so that it is in intimate contact with the surface 52 and valvestem and lls up or closes any space there would be between the upper endof said valve stem and surface 52 of the rocker arm.

During operation of the mechanism, the space between 4the surface 52 andvalve stem may vary slightly due to elongation and/or contraction of thevalve stem, but at each uppermost position of the rocker arm, the spring58 acts on member 50 to cause it to lill up said space.

In elongation of the valve stem, there would be less space between thearm surface 52 and end of valve space to be filled by the member 50 thanwould be the case were contraction of the stem to occur.

As stated, the spring 5S is not sufficient to interfere with the valveclosing function of the spring 24.

Thus, in each valve opening movement of rocker arm, the valve stem isacted upon and depressed through member S0. In the valve closingmovement of the rocker arm, the member 50 is moved outwardly in saidarm. At the uppermost position of the arm, the member 50 is movedinwardly by the spring 58 to lill such space between the valve stem androcker arm surface as there may be.`

In the instance where the surface 52 is disposed above the plane of thehorizontal center line of the rocker arm shaft 14, instead of below theplane as shown, the rnember 50 would then be urged to the right on thevalve opening oscillation to be retained thereat by the valve spring 24until the valve closing action ensues. That is to say, the action isreverse from the action aforedescribed.

Under all operating temperatures, conditions, and engine speeds, themember 50 is automatically adjusted in each cycle of operation toeliminate space between the arm surface and stem, thereby to eliminateobjectionable noise and attain efficient engine operation, as isdesired.

Changes and modifications may be made in the form of the inventionwithout departing from the spirit and scope thereof, and therefore it isdesired to be limited, if at all, by the appended claim rather than bythe foregoing disclosure.

I claim:

In an internal combustion engine the combination with the reciprocablestem of a valve spring actuated to closed position and depressible tovalve open position by the crowned face at one end of a rocker arm foracting on the end of said stem and lifter means for the other end ofsaid arm of means interposed between the crowned face of the rocker armand end of the valve stem for eliminating clearance therebetweencomprising, an elongated relatively rigid wedge member having alongitudinal groove on the under side thereof provided with an elongatedflat lower face on the said end of the stem and being arranged forguiding the wedge member in sliding movements on said end in oppositedirections in a plane at right angles to a plane extending through thelongitudinal axisof said stem, said member having an elongated flatuninterrupted upper face for the crowned end of the rocker arm divergingin one direction from one end thereof relative to the lower at face ofsaid groove to the opposite end thereof, and separate spring meansconnecting said one end of the wedge member and lifter means urging thewedge member in an opposite direction whereby the upper and lower facesthereof operate with a wedging action between the crowned end of therocker arm and end of the valve stem.

References Cited in the le of this patent UNITED STATES PATENTS1,333,160 Cline Mar. 9, 1920 1,701,599 Woolson Feb. 12, 1929 2,019,792Nieman Nov. 5, 1935 2,120,617 Manning Iune 14, 1938 2,493,783 StancliffJan. 10, 1950 FOREIGN PATENTS 1,199 Great Britain Ian. 21, 1905

